The so-called "wind load" on a ceiling, i.e., the pressure exerted by high speed winds on such a ceiling, can be a serious problem in outdoor ceiling constructions such as are found in shopping centers, malls and the like. The wind speeds experienced can, of course, be considerable under hurricane and tornado conditions and the forces generated by such winds can pull the ceiling or parts thereof down. Moreover, ordinary high speed winds can also exert destructive forces on such ceilings. Wind can exert both upwardly and downwardly acting forces on ceilings and these forces are a particular problem in ceiling constructions of the type wherein ceiling panels are suspended from a tee bar or like support (i.e., wherein downwardly depending arms of a tee bar engage and support abutting upright flanges of adjacent ceiling panels) since if enough force is exerted it is possible to pull the panels down from, or otherwise dislodge the panels from, the supports. Other ceiling support arrangements present similar problems.
It is noted that forces similar to those produced by high speed winds can be exerted in other ways including the deliberate actions of vandals, and this can occur even in indoor facilities, such as prisons.
There are, of course, many patents in the field of ceiling constructions and many patents relating to support and/or retaining clips of various kinds including, for example: U.S. Pat. Nos. 1,625,866 (Pawling); 2,170,483 (Place); 3,076,536 (Tinnerman); 3,602,955 (Schwartz); 3,630,554 (Cherniak); 3,809,358 (Hazeley); and 3,823,675 (Farley).